Icon for an Endangered Ecosystem

A rare form of black bear—that often is actually white—faces serious threats to its survival in its British Columbia habitat

01-15-2010
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Jessica Snyder Sachs

FROM THE DOCK of British Columbia’s Hartley Bay, guide Marvin Robinson looks across the waters of the Douglass Channel to Gribbell Island. The 96-square-mile island—thickly forested in hemlock, cedar and fir—is home to the world’s highest concentration of the rare “spirit bear”—a pale color variant of the American black bear. Long revered by the First Nations of British Columbia, scientists dubbed it the Kermode bear in 1905 after one of the first scientists to study the species, Francis Kermode.

More than a third of Gribbell’s black bears are white, says Robinson, a member of the Gitga’at tribe. For the past decade, Robinson has led small expeditions around the island’s edges, where the Gitga’at have built protective boardwalks. He also leads tours on Princess Royal Island, to the north, where 1 in 10 black bears is white. In all, as many as 500 white Kermodes live in British Columbia, the majority on Gribbell and Princess Royal. The entire Kermode subspecies—black or white—numbers at least four times that.

Ecologically, the bear’s importance centers on its value as an icon for a rare and endangered ecosystem. British Columbia’s coast represents the world’s last large, intact temperate rain forest. It is home to an abundance of eagles, ospreys and grizzlies. All five species of Pacific salmon spawn in its streams.

For decades, environmentalists and logging companies battled over this forest’s wealth, in what people here called “The War in the Woods.” In the 1990s, local environmentalists called for an international boycott of their province’s forest products, circulating pictures of charismatic Kermode bears juxtaposed with images of clear-cut mountains.

“The international pressure helped tremendously,” says Merran Smith, of ForestEthics. By 1999, loggers were sitting down with environmentalists, and British Columbia officials were talking with the Gitga’at and other coastal First Nations. In 2006, they announced the Great Bear Rainforest Agreements, which created a core conservancy of 4.4 million acres that includes nearly 500,000 acres of Kermode habitat closed to logging, mining and hunting. Another 10 million acres remain subject to ecosystem-based management, allowing sustainable development within the context of continuing environmental review. The bear some call “Canada’s panda” played a significant role in achieving the historic agreements, all sides concur. Indeed, British Columbia’s First Nations are not alone in cherishing the Kermode. The Kermode is also British Columbia’s provincial mammal and beloved by schoolchildren across Canada. It is even incorporated into one of the mascots for the 2010 Winter Olympics in Vancouver.

The Kermode bear is not a distinct species of black bear but a subspecies with a high frequency of a unique mutation in a pigmentation gene. Population geneticist Kermit Ritland, of the University of British Columbia, led the study that identified the mutation, which involves the same gene that produces the blond coat of golden retrievers. Most of the island’s black-coated bears carry this recessive Kermode gene. Two are needed—one from each parent—to produce a spirit bear.

The gene probably rose to prominence during the last Ice Age, Ritland says. Glaciers then covered the Northwest, cutting off a bear population on a glacier-free strip of northern coastline where inbreeding would have helped increase the frequency of the Kermode gene. Lowered sea levels extended the coast over the continental shelf. When the ice retreated and sea levels rose, many bears were isolated on coastal islands.

While the highest concentrations of Kermodes persist on Gribbell and Princess Royal, lesser numbers roam the coastal mainland, and interbreeding has spread the Kermode gene inland. Occasionally white bears pop up in drier places, such as the sawmill community of Terrace. There a camera-loving Kermode attracted photographers to the town dump for decades.

In the early 1990s, evolutionary biologist Tom Reimchen and his students confirmed that Kermodes were part of a lineage of coastal British Columbia bears that evolved separately from other North American bears during the past half million years. The enduring mystery is why the white-phase gene did not disappear. “If this was something that no longer conveyed an advantage, it should have vanished long ago,” says Reimchen, of British Columbia’s University of Victoria. He and his students have documented intriguing behavioral differences that may shed some light.

During three autumns, graduate student Dan Klinka compared the fishing success of white and black Kermodes. By day, Klinka found, white bears were twice as efficient as black in catching salmon. Klinka then tested Reimchen’s hypothesis that, by day, the white bears were less visible to the evasive salmon. Dressed first in white and then black, Klinka waded into the stream. Initially, salmon scattered. Klinka then timed how long it took for the fish to return to a 6-foot area around him. When he wore white, salmon returned twice as fast and in greater number than when he wore black. “The suggestion is that the white bear is really a salmon bear, that this coat color is a functional adaptation for hunting salmon,” Reimchen says.

Klinka and Reimchen also used fur analysis to show that white Kermodes diverge from their black counterparts in where they feed. Chemical analysis of hair tips—which grow in spring—showed that both white and black Kermodes were feeding on berries and vegetation in the forest—but that the white bears remained closer to the ocean, where plants are enriched by marine nutrients.

Analysis of the mid-hairshaft showed that, by summer, white Kermodes had moved to the ocean’s edge and were feeding on barnacles, mussels and shore vegetation. Meanwhile, black-coated bears remained largely in the alpine. The nutrient differences peaked at the base of hairshafts, which develop in autumn. By then, all the bears were feeding on salmon—but white bears were doing so far more heavily than were black ones. “Our working principle is that the white bear is so anchored to salmon that without the persistence or return of salmon to these coastal creeks, its future is totally compromised,” Reimchen says.

The salmon decline in this region affects more than the beloved spirit bear. Studies suggest that the entire coastal rain forest ecosystem may depend on the infusion of nutrients delivered when salmon return to their natal streams each autumn. Bears, eagles and other predators scatter half-eaten salmon carcasses within the forest.

But the number of returning salmon has been dropping over successive years, says bear biologist Tony Hamilton of the British Columbia Ministry of the Environment. Studies have tied the declines to overfishing, infestations of sea lice from salmon farms and rising water temperatures due to global warming. “For every poor salmon year, there are fewer cubs the next year,” Hamilton says. “If we lose Pacific salmon, we’re going to have difficulty conserving coastal bears regardless of their coat color.”

Logging—even ecosystem-based-management logging—is another concern. “There’s not much soil here to dig a den,” Hamilton explains. Instead, coastal bears den in the hollowed-out stumps of centuries-old cedar and fir. What’s more, their dens need to be watertight and secure enough to exclude hungry wolves and cougars. “That’s not easy to find at any elevation, let alone near the coast,” Hamilton says of the need to keep bear denning in mind when managing timber.

To strengthen Kermode protection, the British Columbia government recently extended its ban of white-bear hunting from the coast to the entire province. Meanwhile, a new threat has emerged: The proposed Enbridge Northern Gateway project involves petroleum pipelines stretching from Alberta’s tar-sand fields—one of the world’s dirtiest oil sources—to a northern British Columbia seaport. Loaded supertankers would then traverse the province’s treacherous coastal waters—closely skirting both Princess Royal and Gribbell Islands. Already numerous ships have hit rocks and sunk in these waters.

Kermode bears may be uniquely vulnerable to oil spills, Hamilton says. He cites studies showing that coastal bears den surprisingly close to the sea and emerge in mid-winter to feed on shore creatures. In addition, the steep coastline often forces bears to travel along the water’s edge.

Canada’s National Energy Board is currently reviewing the Enbridge pipeline proposal, approval of which would end a long-standing moratorium on tanker traffic along British Columbia’s coast. “It makes no sense to be sending tankers with toxic tar sands through this environmentally sensitive region,” Smith argues. But the financial incentives are huge, she admits. “This is a multibillion-dollar project that makes our work with the forestry world look like a tea party.”

Jessica Snyder Sachs is the author of Good Germs, Bad Germs: Health and Survival in a Bacterial World (Farrar, Straus, and Giroux) and Corpse: Nature, Forensics, and the Struggle to Pinpoint Time of Death (Perseus).

A Question of Color The American black bear also can be white, brown, reddish brown (called cinnamon) and even blue-gray. Bears of different colors can be born in the same litter.

NWF Action: Bearing with Us During its long history of working on behalf of bears, NWF has helped lead efforts to protect grizzlies and their habitat in Alaska, Wyoming and Montana, to protect wetlands important to jeopardized black bears in Louisiana and in Mississippi’s Yazoo Basin, and to reduce global warming, a key threat to polar bear survival.